1. Field of the Invention
The present invention relates to a mechanism, incorporated in a retractable photographing (imaging) lens (retractable lens barrel), for retracting a part of a plurality of optical elements, constituting a photographing optical system, to a position deviating from the photographing optical axis of the photographing optical system when the photographing lens is fully retracted.
2. Description of the Related Art
Miniaturization of lens barrels incorporated in optical devices such as cameras has been in increasing demand. Above all, further miniaturization of retractable photographing lenses, specifically the length thereof in a non-operating state, has been in strong demand. To meet such demands, the inventor of the present invention has proposed a retractable photographing lens disclosed in U.S. patent application Ser. No. 10/368,342 in which an optical element (retractable optical element) of a photographing optical system is retracted to a position deviating from the photographing optical axis of the photographing optical system while the optical element (together with other optical elements of the photographing optical system) is retracted along the optical axis of the photographing optical system when the photographing lens is fully retracted. The mechanism achieving such complicated operations of the optical elements is required to operate with a high degree of accuracy, and is further required not to damage the optical performance of the retractable optical element even if a malfunction of some kind occurs in the retracting operation of the zoom lens.